The inline density measurement of liquids is now possible with a newly-developed, low-cost, Liquiphant M sensor. In food and beverage, chemical and mining applications, this density measuring sensor can reduce material wastage, increase product quality and optimise control of the process.
In process industries, many activities rely on accurate and reliable density measurement; this includes the dosing of preliminary, interim and final products; determining exact density or concentration; monitoring quality and controlling processes. Food processing often requires the combination of multiple ingredients and progressively monitoring density enables operators to determine the exact amount of ingredient to be added.
Endress+Hauser have been using the ‘vibrating fork’ principle to monitor levels of liquids for over 30 years and, with Liquiphant M, have adapted this technology to enable the accurate and in situ measurement of liquid density. The resonant frequency of the Liquiphant M’s vibrating fork changes with the varying densities of the materials in which it is placed. This change is used to compute the density or concentration of the medium resulting in instantaneous, repeatable density measurements.
Sugar is widely used in food processing and accurately measuring its content (degrees Brix) is critical for cost efficiency and product quality. The associated Liquiphant FML621 density calculator displays this information in measurements relevant to the process, ºBrix for sugar, ºBaume for salts, ºPlato for brewing or any other density derived units specific to an application.
Plants typically invest in extensive offline procedures and expensive laboratory analysis to determine concentration levels. The time interval between taking the sample and getting the analysed results with an offline process often resulted in wastage and poor quality product as remedial action was delayed.
Liquiplant M offers a cost-effective alternative and provides reliable inline density measurement at a glance. This allows immediate adjustments to the process and increases plant availability, improves process control and reduces material wastage.
Density measurement is also critical in mining applications where the flocculent is added to a liquid to make solids ‘stickier’. The solid particles adhere to others, become heavier, drop to the bottom and are extracted. The Liquiphant M can be used to accurately control the rate and amount of flocculent and thereby minimise waste.
The Liquiphant M density measurement system can be used across process industries for concentration measurement, quality statements and purity indications or even as a basic variable in calculations and simulations. To boost efficiencies and also to aid in the repeatability of a process, it is important to capture data on the effects of adjustments such as heating and cooling, stirring speeds, rates and amounts of ingredients added. There are also legal requirements, in the pharmaceutical industry for example, to maintain detailed records of each batch manufactured. The digital readings from the in situ Liquiphant M can be critical in this regard.
A Liquiphant device can be used as a dual-purpose probe – to measure density and monitor liquid levels. A typical application is dry-run protection where a density measuring probe switches over to measure level at the end of a process and advises the operator to stop the pump once the vessel is empty.
The versatile Liquiphant M can also be installed in petroleum plants which often use the same pipeline to transfer a variety of liquids between tanks. After a batch of fluid goes through, a pellet cleans the pipeline before another fluid is pumped in. The operator is able to use the installed Liquiphant M’s density measurements to detect and ascertain that the correct fluid has been transferred.
Over the past three decades, Endress+Hauser have refined the technology so that Liquiphant probes operate in materials with high abrasion, high corrosion, high temperature and high toxicity. It is also possible to combine Liquiphant M with other measuring instruments to provide additional values such as mass or massflow information.